Before many-worlds, reality had always been viewed as a single unfolding history. Many-worlds, however, views historical structure and interpretation of classical mechanics second edition pdf as a many-branched tree, wherein every possible quantum outcome is realised.
Nobel prize seems to be describing several different histories, they are “not alternatives but all really happen simultaneously”. This is the earliest known reference to the many-worlds. Everett’s theory, which had been largely ignored for the first decade after publication. Under scrutiny of the environment, only pointer states remain unchanged. Other states decohere into mixtures of stable pointer states that can persist, and, in this sense, exist: They are einselected. These ideas complement MWI and bring the interpretation in line with our perception of reality.
Deutsch is dismissive that many-worlds is an “interpretation”, saying that calling it an interpretation “is like talking about dinosaurs as an ‘interpretation’ of fossil records. Unsourced material may be challenged and removed. Everett’s work provided such an alternative interpretation. Since the wavefunction merely appears to have collapsed then, Everett reasoned, there was no need to actually assume that it had collapsed. Hawking saying that MWI is “trivially true”. In the same interview, he also said, “But, look: All that one does, really, is to calculate conditional probabilities—in other words, the probability of A happening, given B.
I think that that’s all the many worlds interpretation is. Some people overlay it with a lot of mysticism about the wave function splitting into different parts. But all that you’re calculating is conditional probabilities. He’s worried that Schrödinger’s cat is in a quantum state, where it is half alive and half dead.
He feels that can’t correspond to reality. But that doesn’t bother me. I don’t demand that a theory correspond to reality because I don’t know what it is. Reality is not a quality you can test with litmus paper.